- Iron (II) ions, Fe is a reducing agent while manganate (VII) ions, MnO4- , is an oxidizing agent - Iron (II) ions, Fe2+ undergoes oxidation process while manganate (VII) ions, MnO4- , undergoes reduction process 

- Oxidation half equation: Fe2+ →Fe3+ + e- 

- Reduction half equation: MnO4- + 8H+ + 5e- → Mn2+ + 4H20

- Enode value of Iron (II) ions, Fe2+ is lower than manganate (VII) ions, MnO4-

- Iron (II) ions, Fe2+ releases 2 electrons and are oxidised to iron (III) ions, Fe3+

- Manganate (VII) ions, MnO4- , receive 7 electrons and are reduced to manganese (II) ions, Mn2+

Experiment II

- Magnesium, Mg is a reducing agent while iron (II) ion, Fe2+ an oxidizing agent 

- Magnesium, Mg undergoes oxidation process while iron (II) ion, Fe2+ undergoes reduction process 

- Oxidation half equation: Mg → Mg2+ + 2e

- Reduction half equation: Fe2+ + 2e- → Fe 

- Enode value of magnesium ion, Mg2+is lower than iron (II)ion, Fe2+ 

- Magnesium releases 2 electrons to produce magnesium ion, Mg2+. Iron (II)ion, Fe2+ receives 2 electrons to produce iron.

Experiment III

- Iron atom is an reducing agent 

- Iron atom undergoes oxidation process

Oxidation half equation: Fe → Fe 2+ + 2e- 

- Enode value of iron metal, Fe is lower than copper metal, Cu 

- Iron atom releases 2 electrons to form iron (II)ion, Fe2+

- Iron (II) Sulphate undergoes oxidation because the oxidation number of iron in iron

(II) sulphate increase form +2 to +3

- Iron (II) sulphate is the reducing agent 

- Bromine undergoes reduction because the oxidation number of bromine decreases

from 0 to -1

 - Bromine water is the oxidising agent

Half equation 

At electrode L:

- 2Fe 2+ → 2Fe3+ + 2e- 

At electrode M:

 - Br2 +2e -> 2Br-

Overall ionic equation: - 2Fe2+ + Br2 → 2Fe3+ + 2Br-

Materials : Agar solution, phenolphthalein, potassium hexacyanoferrate(III), K3Fe(CN)6 solution, iron nails, magnesium ribbon, Mg, tin strip, Sn and copper strip, Cu
Procedure: 

Set I - Iron undergoes oxidation or corrosion instead of Tin.

Set II - Magnesium undergoes oxidation or corrosion instead of iron.

Set III - Iron undergoes oxidation or corrosion instead of copper.

Apparatus : U-tube, galvanometer, connecting wires with crocodile clips, galvanometer, retort stand, carbon electrodes, dropper and test tube

Procedure : 

1. Measure and pour 1 mol dm-3 of sulphuric acid, H2SO4 into the 7-tube until half full

and clamp it vertically. 

2. Measure and pour 0.5 mol dm-3 of potassium bromide, KBr solution into one arm using dropper. 

3. Measure and pour 0.5 mol dm-3 of iron (III) sulphate, Fe2(SO4)3 solution into other arm of U-tube. 

4. Dip the carbon electrodes into the solutions and connect to the galvanometer using

connecting wires. 

5. Observe the galvanometer pointer and the colour changes of the solutions of potassium

bromide, KBr solution and iron (III) sulphate, Fe2(SO4)3 solution.

- Oxidising agent: Iron (III) sulphate solution

- Half equation of oxidising agent: Fe3+ + 2e- → Fe2+ 

- The brown iron (III) sulphate solution turns green 

Confirmatory test for Fe3+ :

- Sodium hydroxide solution is added to the mixture until excess. Green precipitate is formed insoluble in excess.

- Reducing agent : Potassium bromide solution 

- Half equation of reducing agent : 2Br- → Br2 + 2e-

- The colourless potassium bromide solution turns brown